The African coelacanth genome provides insights into tetrapod evolution:
- Amemiya, Chris T, Alföldi, Jessica, Lee, Alison P, Fan, Shaohua, Philippe, Herve´, MacCallum, Iain, Braasch, Ingo, Manousaki, Tereza, Schneider, Igor, Rohner, Nicolas, Organ, Chris, Chalopin, Domitille, Smith, Jeramiah J, Robinson, Mark, Dorrington, Rosemary A, Gerdol, Marco, Aken, Bronwen, Biscotti, Maria Assunta, Barucca, Marco, Baurain, Denis, Berlin, Aaron, Blatch, Gregory L, Buonocore, Francesco, Burmester, Thorsten, Campbell, Michael S, Canapa, Adriana, Cannon, John P, Christoffels, Alan, De Moro, Gianluca, Edkins, Adrienne L, Fan, Lin, Fausto, Anna Maria, Feiner, Nathalie, Forconi, Mariko, Gamieldien, Junaid, Gnerre, Sante, Gnirke, Andreas, Goldstone, Jared V, Haerty, Wilfried, Hahn, Mark E, Hesse, Uljana, Hoffmann, Steve, Johnson, Jeremy, Karchner, Sibel I, Kuraku, Shigehiro, Lara, Marcia, Levin, Joshua Z, Litman, Gary W, Mauceli, Evan, Miyake, Tsutomu, Mueller, M Gail, Nelson, David R, Nitsche, Anne, Olmo, Ettore, Ota, Tatsuya, Pallavicini, Alberto, Panji, Sumir, Picone, Barbara, Ponting, Chris P, Prohaska, Sonja J, Przybylski, Dariusz, Ratan Saha, Nil, Ravi, Vydianathan, Ribeiro, Filipe J, Sauka-Spengler, Tatjana, Scapigliati, Giuseppe, Searle, Stephen M J, Sharpe, Ted, Simakov, Oleg, Stadler, Peter F, Stegeman, John J, Sumiyama, Kenta, Tabbaa, Diana, Tafer, Hakim, Turner-Maier, Jason, van Heusden, Peter, White, Simon, Williams, Louise, Yandell, Mark, Brinkmann, Henner, Volff, Jean-Nicolas, Tabin, Clifford J, Shubin, Neil, Schartl, Manfred, Jaffe, David B, Postlethwait, John H, Venkatesh, Byrappa, Di Palma, Frederica, Lander, Eric S, Meyer, Axel, Lindblad-Toh, Kerstin
- Authors: Amemiya, Chris T , Alföldi, Jessica , Lee, Alison P , Fan, Shaohua , Philippe, Herve´ , MacCallum, Iain , Braasch, Ingo , Manousaki, Tereza , Schneider, Igor , Rohner, Nicolas , Organ, Chris , Chalopin, Domitille , Smith, Jeramiah J , Robinson, Mark , Dorrington, Rosemary A , Gerdol, Marco , Aken, Bronwen , Biscotti, Maria Assunta , Barucca, Marco , Baurain, Denis , Berlin, Aaron , Blatch, Gregory L , Buonocore, Francesco , Burmester, Thorsten , Campbell, Michael S , Canapa, Adriana , Cannon, John P , Christoffels, Alan , De Moro, Gianluca , Edkins, Adrienne L , Fan, Lin , Fausto, Anna Maria , Feiner, Nathalie , Forconi, Mariko , Gamieldien, Junaid , Gnerre, Sante , Gnirke, Andreas , Goldstone, Jared V , Haerty, Wilfried , Hahn, Mark E , Hesse, Uljana , Hoffmann, Steve , Johnson, Jeremy , Karchner, Sibel I , Kuraku, Shigehiro , Lara, Marcia , Levin, Joshua Z , Litman, Gary W , Mauceli, Evan , Miyake, Tsutomu , Mueller, M Gail , Nelson, David R , Nitsche, Anne , Olmo, Ettore , Ota, Tatsuya , Pallavicini, Alberto , Panji, Sumir , Picone, Barbara , Ponting, Chris P , Prohaska, Sonja J , Przybylski, Dariusz , Ratan Saha, Nil , Ravi, Vydianathan , Ribeiro, Filipe J , Sauka-Spengler, Tatjana , Scapigliati, Giuseppe , Searle, Stephen M J , Sharpe, Ted , Simakov, Oleg , Stadler, Peter F , Stegeman, John J , Sumiyama, Kenta , Tabbaa, Diana , Tafer, Hakim , Turner-Maier, Jason , van Heusden, Peter , White, Simon , Williams, Louise , Yandell, Mark , Brinkmann, Henner , Volff, Jean-Nicolas , Tabin, Clifford J , Shubin, Neil , Schartl, Manfred , Jaffe, David B , Postlethwait, John H , Venkatesh, Byrappa , Di Palma, Frederica , Lander, Eric S , Meyer, Axel , Lindblad-Toh, Kerstin
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165030 , vital:41202 , DOI: 10.1038/nature12027
- Description: The discovery of a living coelacanth specimen in 1938 was remarkable, as this lineage of lobe-finned fish was thought to have become extinct 70 million years ago. The modern coelacanth looks remarkably similar to many of its ancient relatives, and its evolutionary proximity to our own fish ancestors provides a glimpse of the fish that first walked on land. Here we report the genome sequence of the African coelacanth, Latimeria chalumnae. Through a phylogenomic analysis, we conclude that the lungfish, and not the coelacanth, is the closest living relative of tetrapods. Coelacanth protein-coding genes are significantly more slowly evolving than those of tetrapods, unlike other genomic features. Analyses of changes in genes and regulatory elements during the vertebrate adaptation to land highlight genes involved in immunity, nitrogen excretion and the development of fins, tail, ear, eye, brain and olfaction. Functional assays of enhancers involved in the fin-to-limb transition and in the emergence of extra-embryonic tissues show the importance of the coelacanth genome as a blueprint for understanding tetrapod evolution.
- Full Text:
- Date Issued: 2013
- Authors: Amemiya, Chris T , Alföldi, Jessica , Lee, Alison P , Fan, Shaohua , Philippe, Herve´ , MacCallum, Iain , Braasch, Ingo , Manousaki, Tereza , Schneider, Igor , Rohner, Nicolas , Organ, Chris , Chalopin, Domitille , Smith, Jeramiah J , Robinson, Mark , Dorrington, Rosemary A , Gerdol, Marco , Aken, Bronwen , Biscotti, Maria Assunta , Barucca, Marco , Baurain, Denis , Berlin, Aaron , Blatch, Gregory L , Buonocore, Francesco , Burmester, Thorsten , Campbell, Michael S , Canapa, Adriana , Cannon, John P , Christoffels, Alan , De Moro, Gianluca , Edkins, Adrienne L , Fan, Lin , Fausto, Anna Maria , Feiner, Nathalie , Forconi, Mariko , Gamieldien, Junaid , Gnerre, Sante , Gnirke, Andreas , Goldstone, Jared V , Haerty, Wilfried , Hahn, Mark E , Hesse, Uljana , Hoffmann, Steve , Johnson, Jeremy , Karchner, Sibel I , Kuraku, Shigehiro , Lara, Marcia , Levin, Joshua Z , Litman, Gary W , Mauceli, Evan , Miyake, Tsutomu , Mueller, M Gail , Nelson, David R , Nitsche, Anne , Olmo, Ettore , Ota, Tatsuya , Pallavicini, Alberto , Panji, Sumir , Picone, Barbara , Ponting, Chris P , Prohaska, Sonja J , Przybylski, Dariusz , Ratan Saha, Nil , Ravi, Vydianathan , Ribeiro, Filipe J , Sauka-Spengler, Tatjana , Scapigliati, Giuseppe , Searle, Stephen M J , Sharpe, Ted , Simakov, Oleg , Stadler, Peter F , Stegeman, John J , Sumiyama, Kenta , Tabbaa, Diana , Tafer, Hakim , Turner-Maier, Jason , van Heusden, Peter , White, Simon , Williams, Louise , Yandell, Mark , Brinkmann, Henner , Volff, Jean-Nicolas , Tabin, Clifford J , Shubin, Neil , Schartl, Manfred , Jaffe, David B , Postlethwait, John H , Venkatesh, Byrappa , Di Palma, Frederica , Lander, Eric S , Meyer, Axel , Lindblad-Toh, Kerstin
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165030 , vital:41202 , DOI: 10.1038/nature12027
- Description: The discovery of a living coelacanth specimen in 1938 was remarkable, as this lineage of lobe-finned fish was thought to have become extinct 70 million years ago. The modern coelacanth looks remarkably similar to many of its ancient relatives, and its evolutionary proximity to our own fish ancestors provides a glimpse of the fish that first walked on land. Here we report the genome sequence of the African coelacanth, Latimeria chalumnae. Through a phylogenomic analysis, we conclude that the lungfish, and not the coelacanth, is the closest living relative of tetrapods. Coelacanth protein-coding genes are significantly more slowly evolving than those of tetrapods, unlike other genomic features. Analyses of changes in genes and regulatory elements during the vertebrate adaptation to land highlight genes involved in immunity, nitrogen excretion and the development of fins, tail, ear, eye, brain and olfaction. Functional assays of enhancers involved in the fin-to-limb transition and in the emergence of extra-embryonic tissues show the importance of the coelacanth genome as a blueprint for understanding tetrapod evolution.
- Full Text:
- Date Issued: 2013
The complex immunological and inflammatory network of adipose tissue in obesity
- Apostolopoulos, Vasso, De Courten, Maximilian P J, Stojanovska, Lily, Blatch, Gregory L, Tangalakis, Kathy, De Courten, Barbora
- Authors: Apostolopoulos, Vasso , De Courten, Maximilian P J , Stojanovska, Lily , Blatch, Gregory L , Tangalakis, Kathy , De Courten, Barbora
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66120 , vital:28905 , https://doi.org/10.1002/mnfr.201500272
- Description: publisher version , A number of approaches have been utilized in the prevention, management, and treatment of obesity, including, surgery, medication, diet, exercise, and overall lifestyle changes. Despite these interventions, the prevalence of obesity and the various disorders related to it is growing. In obesity, there is a constant state of chronic low‐grade inflammation which is characterized by activation and infiltration of pro‐inflammatory immune cells and a dysregulated production of high levels of pro‐inflammatory cytokines. This pro‐inflammatory milieu contributes to insulin resistance, type‐2 diabetes, cardiovascular disease, and other related co‐morbidities. The roles of the innate (macrophages, neutrophils, eosinophils, mast cells, NK cells, MAIT cells) and the adaptive (CD4 T cells, CD8 T cells, regulatory T cells, and B cells) immune responses and the roles of adipokines and cytokines in adipose tissue inflammation and obesity are discussed. An understanding of the crosstalk between the immune system and adipocytes may shed light in better treatment modalities for obesity and obesity‐related diseases.
- Full Text: false
- Date Issued: 2016
- Authors: Apostolopoulos, Vasso , De Courten, Maximilian P J , Stojanovska, Lily , Blatch, Gregory L , Tangalakis, Kathy , De Courten, Barbora
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66120 , vital:28905 , https://doi.org/10.1002/mnfr.201500272
- Description: publisher version , A number of approaches have been utilized in the prevention, management, and treatment of obesity, including, surgery, medication, diet, exercise, and overall lifestyle changes. Despite these interventions, the prevalence of obesity and the various disorders related to it is growing. In obesity, there is a constant state of chronic low‐grade inflammation which is characterized by activation and infiltration of pro‐inflammatory immune cells and a dysregulated production of high levels of pro‐inflammatory cytokines. This pro‐inflammatory milieu contributes to insulin resistance, type‐2 diabetes, cardiovascular disease, and other related co‐morbidities. The roles of the innate (macrophages, neutrophils, eosinophils, mast cells, NK cells, MAIT cells) and the adaptive (CD4 T cells, CD8 T cells, regulatory T cells, and B cells) immune responses and the roles of adipokines and cytokines in adipose tissue inflammation and obesity are discussed. An understanding of the crosstalk between the immune system and adipocytes may shed light in better treatment modalities for obesity and obesity‐related diseases.
- Full Text: false
- Date Issued: 2016
Hsp70/Hsp90 organising protein (hop): beyond interactions with chaperones and prion proteins
- Baindur-Hudson, Swati, Edkins, Adrienne L, Blatch, Gregory L
- Authors: Baindur-Hudson, Swati , Edkins, Adrienne L , Blatch, Gregory L
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/164852 , vital:41178 , ISBN 978-3-319-11730-0 , DOI: 10.1007/978-3-319-11731-7_3
- Description: The Hsp70/Hsp90 organising protein (Hop), also known as stress-inducible protein 1 (STI1), has received considerable attention for diverse cellular functions in both healthy and diseased states. There is extensive evidence that intracellular Hop is a co-chaperone of the major chaperones Hsp70 and Hsp90, playing an important role in the productive folding of Hsp90 client proteins. Consequently, Hop is implicated in a number of key signalling pathways, including aberrant pathways leading to cancer. However, Hop is also secreted and it is now well established that Hop also serves as a receptor for the prion protein, PrPC.
- Full Text:
- Date Issued: 2015
- Authors: Baindur-Hudson, Swati , Edkins, Adrienne L , Blatch, Gregory L
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/164852 , vital:41178 , ISBN 978-3-319-11730-0 , DOI: 10.1007/978-3-319-11731-7_3
- Description: The Hsp70/Hsp90 organising protein (Hop), also known as stress-inducible protein 1 (STI1), has received considerable attention for diverse cellular functions in both healthy and diseased states. There is extensive evidence that intracellular Hop is a co-chaperone of the major chaperones Hsp70 and Hsp90, playing an important role in the productive folding of Hsp90 client proteins. Consequently, Hop is implicated in a number of key signalling pathways, including aberrant pathways leading to cancer. However, Hop is also secreted and it is now well established that Hop also serves as a receptor for the prion protein, PrPC.
- Full Text:
- Date Issued: 2015
STIP1/HOP regulates the actin cytoskeleton through interactions with actin and changes in actin-binding proteins cofilin and profilin:
- Beckley, Samantha Joy, Hunter, Morgan C, Kituyi, Sarah N, Wingate, Ianthe, Chakraborty, Abantika, Schwarz, Kelly, Makhubu, Matodzi P, Rousseau, Robert P, Ruck, Duncan K, de la Mare, Jo-Anne, Blatch, Gregory L, Edkins, Adrienne L
- Authors: Beckley, Samantha Joy , Hunter, Morgan C , Kituyi, Sarah N , Wingate, Ianthe , Chakraborty, Abantika , Schwarz, Kelly , Makhubu, Matodzi P , Rousseau, Robert P , Ruck, Duncan K , de la Mare, Jo-Anne , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165373 , vital:41238 , https://doi.org/10.3390/ijms21093152
- Description: Cell migration plays a vital role in both health and disease. It is driven by reorganization of the actin cytoskeleton, which is regulated by actin-binding proteins cofilin and profilin. Stress-inducible phosphoprotein 1 (STIP1) is a well-described co-chaperone of the Hsp90 chaperone system, and our findings identify a potential regulatory role of STIP1 in actin dynamics. We show that STIP1 can be isolated in complex with actin and Hsp90 from HEK293T cells and directly interacts with actin in vitro via the C-terminal TPR2AB-DP2 domain of STIP1, potentially due to a region spanning two putative actin-binding motifs. We found that STIP1 could stimulate the in vitro ATPase activity of actin, suggesting a potential role in the modulation of F-actin formation. Interestingly, while STIP1 depletion in HEK293T cells had no major effect on total actin levels, it led to increased nuclear accumulation of actin, disorganization of F-actin structures, and an increase and decrease in cofilin and profilin levels, respectively. This study suggests that STIP1 regulates the cytoskeleton by interacting with actin, or via regulating the ratio of proteins known to affect actin dynamics.
- Full Text:
- Date Issued: 2020
- Authors: Beckley, Samantha Joy , Hunter, Morgan C , Kituyi, Sarah N , Wingate, Ianthe , Chakraborty, Abantika , Schwarz, Kelly , Makhubu, Matodzi P , Rousseau, Robert P , Ruck, Duncan K , de la Mare, Jo-Anne , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165373 , vital:41238 , https://doi.org/10.3390/ijms21093152
- Description: Cell migration plays a vital role in both health and disease. It is driven by reorganization of the actin cytoskeleton, which is regulated by actin-binding proteins cofilin and profilin. Stress-inducible phosphoprotein 1 (STIP1) is a well-described co-chaperone of the Hsp90 chaperone system, and our findings identify a potential regulatory role of STIP1 in actin dynamics. We show that STIP1 can be isolated in complex with actin and Hsp90 from HEK293T cells and directly interacts with actin in vitro via the C-terminal TPR2AB-DP2 domain of STIP1, potentially due to a region spanning two putative actin-binding motifs. We found that STIP1 could stimulate the in vitro ATPase activity of actin, suggesting a potential role in the modulation of F-actin formation. Interestingly, while STIP1 depletion in HEK293T cells had no major effect on total actin levels, it led to increased nuclear accumulation of actin, disorganization of F-actin structures, and an increase and decrease in cofilin and profilin levels, respectively. This study suggests that STIP1 regulates the cytoskeleton by interacting with actin, or via regulating the ratio of proteins known to affect actin dynamics.
- Full Text:
- Date Issued: 2020
Molecular chaperones in biology, medicine and protein biotechnology
- Boshoff, Aileen, Nicoll, William S, Hennessy, Fritha, Ludewig, M H, Daniel, Sheril, Modisakeng, Keoagile W, Shonhai, Addmore, McNamara, Caryn, Bradley, Graeme, Blatch, Gregory L
- Authors: Boshoff, Aileen , Nicoll, William S , Hennessy, Fritha , Ludewig, M H , Daniel, Sheril , Modisakeng, Keoagile W , Shonhai, Addmore , McNamara, Caryn , Bradley, Graeme , Blatch, Gregory L
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6457 , http://hdl.handle.net/10962/d1004479
- Description: Molecular chaperones consist of several highly conserved families of proteins, many of which consist of heat shock proteins. The primary function of molecular chaperones is to facilitate the folding or refolding of proteins, and therefore they play an important role in diverse cellular processes including protein synthesis, protein translocation, and the refolding or degradation of proteins after cell stress. Cells are often exposed to different stressors, resulting in protein misfolding and aggregation. It is now well established that the levels of certain molecular chaperones are elevated during stress to provide protection to the cell. The focus of this review is on the impact of molecular chaperones in biology, medicine and protein biotechnology, and thus covers both fundamental and applied aspects of chaperone biology. Attention is paid to the functions and applications of molecular chaperones from bacterial and eukaryotic cells, focusing on the heat shock proteins 90 (Hsp90), 70 (Hsp70) and 40 (Hsp40) classes of chaperones, respectively. The role of these classes of chaperones in human diseases is discussed, as well as the parts played by chaperones produced by the causative agents of malaria and trypanosomiasis. Recent advances have seen the application of chaperones in improving the yields of a particular target protein in recombinant protein production. The prospects for the targeted use of molecular chaperones for the over-production of recombinant proteins is critically reviewed, and current research on these chaperones at Rhodes University is also discussed.
- Full Text:
- Date Issued: 2004
- Authors: Boshoff, Aileen , Nicoll, William S , Hennessy, Fritha , Ludewig, M H , Daniel, Sheril , Modisakeng, Keoagile W , Shonhai, Addmore , McNamara, Caryn , Bradley, Graeme , Blatch, Gregory L
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6457 , http://hdl.handle.net/10962/d1004479
- Description: Molecular chaperones consist of several highly conserved families of proteins, many of which consist of heat shock proteins. The primary function of molecular chaperones is to facilitate the folding or refolding of proteins, and therefore they play an important role in diverse cellular processes including protein synthesis, protein translocation, and the refolding or degradation of proteins after cell stress. Cells are often exposed to different stressors, resulting in protein misfolding and aggregation. It is now well established that the levels of certain molecular chaperones are elevated during stress to provide protection to the cell. The focus of this review is on the impact of molecular chaperones in biology, medicine and protein biotechnology, and thus covers both fundamental and applied aspects of chaperone biology. Attention is paid to the functions and applications of molecular chaperones from bacterial and eukaryotic cells, focusing on the heat shock proteins 90 (Hsp90), 70 (Hsp70) and 40 (Hsp40) classes of chaperones, respectively. The role of these classes of chaperones in human diseases is discussed, as well as the parts played by chaperones produced by the causative agents of malaria and trypanosomiasis. Recent advances have seen the application of chaperones in improving the yields of a particular target protein in recombinant protein production. The prospects for the targeted use of molecular chaperones for the over-production of recombinant proteins is critically reviewed, and current research on these chaperones at Rhodes University is also discussed.
- Full Text:
- Date Issued: 2004
Hsp90α/β associates with the GSK3β/axin1/phospho-β-catenin complex in the human MCF-7 epithelial breast cancer model:
- Cooper, Leanne C, Prinsloo, Earl, Edkins, Adrienne L, Blatch, Gregory L
- Authors: Cooper, Leanne C , Prinsloo, Earl , Edkins, Adrienne L , Blatch, Gregory L
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165096 , vital:41208 , DOI: 10.1016/j.bbrc.2011.08.136
- Description: Hsp90α/β, the signal transduction chaperone, maintains intracellular communication in normal, stem, and cancer cells. The well characterised association of Hsp90α/β with its client kinases form the framework of multiple signalling networks. GSK3β, a known Hsp90α/β client, mediates β-catenin phosphorylation as part of a cytoplasmic destruction complex which targets phospho-β-catenin to the 26S proteasome. The canonical Wnt/β-catenin pathway promotes stem cell self-renewal as well as oncogenesis. The degree of Hsp90α/β involvement in Wnt/β-catenin signalling needs clarification. Here, we describe the association of Hsp90α/β with GSK3β, β-catenin, phospho-β-catenin and the molecular scaffold, axin1, in the human MCF-7 epithelial breast cancer cell model using selective inhibition of Hsp90α/β, confocal laser scanning microscopy and immunoprecipitation. Our findings suggest that Hsp90α/β modulates the phosphorylation of β-catenin by interaction in common complex with GSK3β/axin1/β-catenin.
- Full Text:
- Date Issued: 2011
- Authors: Cooper, Leanne C , Prinsloo, Earl , Edkins, Adrienne L , Blatch, Gregory L
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165096 , vital:41208 , DOI: 10.1016/j.bbrc.2011.08.136
- Description: Hsp90α/β, the signal transduction chaperone, maintains intracellular communication in normal, stem, and cancer cells. The well characterised association of Hsp90α/β with its client kinases form the framework of multiple signalling networks. GSK3β, a known Hsp90α/β client, mediates β-catenin phosphorylation as part of a cytoplasmic destruction complex which targets phospho-β-catenin to the 26S proteasome. The canonical Wnt/β-catenin pathway promotes stem cell self-renewal as well as oncogenesis. The degree of Hsp90α/β involvement in Wnt/β-catenin signalling needs clarification. Here, we describe the association of Hsp90α/β with GSK3β, β-catenin, phospho-β-catenin and the molecular scaffold, axin1, in the human MCF-7 epithelial breast cancer cell model using selective inhibition of Hsp90α/β, confocal laser scanning microscopy and immunoprecipitation. Our findings suggest that Hsp90α/β modulates the phosphorylation of β-catenin by interaction in common complex with GSK3β/axin1/β-catenin.
- Full Text:
- Date Issued: 2011
Nuclear translocation of the phosphoprotein Hop (Hsp70/Hsp90 organizing protein) occurs under heat shock, and its proposed nuclear localization signal is involved in Hsp90 binding
- Daniel, Sheril, Bradley, Graeme, Longshaw, Victoria M, Söti, Csaba, Csermely, Peter, Blatch, Gregory L
- Authors: Daniel, Sheril , Bradley, Graeme , Longshaw, Victoria M , Söti, Csaba , Csermely, Peter , Blatch, Gregory L
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6472 , http://hdl.handle.net/10962/d1005951 , http://dx.doi.org/10.1016/j.bbamcr.2008.01.014
- Description: The Hsp70–Hsp90 complex is implicated in the folding and regulation of numerous signaling proteins, and Hop, the Hsp70–Hsp90 Organizing Protein, facilitates the association of this multichaperone machinery. Phosphatase treatment of mouse cell extracts reduced the number of Hop isoforms compared to untreated extracts, providing the first direct evidence that Hop was phosphorylated in vivo. Furthermore, surface plasmon resonance (SPR) spectroscopy showed that a cdc2 kinase phosphorylation mimic of Hop had reduced affinity for Hsp90 binding. Hop was predominantly cytoplasmic, but translocated to the nucleus in response to heat shock. A putative bipartite nuclear localization signal (NLS) has been identified within the Hsp90-binding domain of Hop. Although substitution of residues within the major arm of this proposed NLS abolished Hop–Hsp90 interaction as determined by SPR, this was not sufficient to prevent the nuclear accumulation of Hop under leptomycin-B treatment and heat shock conditions. These results showed for the first time that the subcellular localization of Hop was stress regulated and that the major arm of the putative NLS was not directly important for nuclear translocation but was critical for Hop–Hsp90 association in vitro. We propose a model in which the association of Hop with Hsp90 and the phosphorylated status of Hop both play a role in the mechanism of nucleo-cytoplasmic shuttling of Hop.
- Full Text:
- Date Issued: 2008
- Authors: Daniel, Sheril , Bradley, Graeme , Longshaw, Victoria M , Söti, Csaba , Csermely, Peter , Blatch, Gregory L
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6472 , http://hdl.handle.net/10962/d1005951 , http://dx.doi.org/10.1016/j.bbamcr.2008.01.014
- Description: The Hsp70–Hsp90 complex is implicated in the folding and regulation of numerous signaling proteins, and Hop, the Hsp70–Hsp90 Organizing Protein, facilitates the association of this multichaperone machinery. Phosphatase treatment of mouse cell extracts reduced the number of Hop isoforms compared to untreated extracts, providing the first direct evidence that Hop was phosphorylated in vivo. Furthermore, surface plasmon resonance (SPR) spectroscopy showed that a cdc2 kinase phosphorylation mimic of Hop had reduced affinity for Hsp90 binding. Hop was predominantly cytoplasmic, but translocated to the nucleus in response to heat shock. A putative bipartite nuclear localization signal (NLS) has been identified within the Hsp90-binding domain of Hop. Although substitution of residues within the major arm of this proposed NLS abolished Hop–Hsp90 interaction as determined by SPR, this was not sufficient to prevent the nuclear accumulation of Hop under leptomycin-B treatment and heat shock conditions. These results showed for the first time that the subcellular localization of Hop was stress regulated and that the major arm of the putative NLS was not directly important for nuclear translocation but was critical for Hop–Hsp90 association in vitro. We propose a model in which the association of Hop with Hsp90 and the phosphorylated status of Hop both play a role in the mechanism of nucleo-cytoplasmic shuttling of Hop.
- Full Text:
- Date Issued: 2008
The Malarial Exported PFA0660w Is an Hsp40 Co-Chaperone of PfHsp70-x
- Daniyan, Michael O, Boshoff, Aileen, Prinsloo, Earl, Pesce, Eva-Rachele, Blatch, Gregory L
- Authors: Daniyan, Michael O , Boshoff, Aileen , Prinsloo, Earl , Pesce, Eva-Rachele , Blatch, Gregory L
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66098 , vital:28901 , https://doi.org/10.1371/journal.pone.0148517
- Description: publisher version , Plasmodium falciparum, the human pathogen responsible for the most dangerous malaria infection, survives and develops in mature erythrocytes through the export of proteins needed for remodelling of the host cell. Molecular chaperones of the heat shock protein (Hsp) family are prominent members of the exportome, including a number of Hsp40s and a Hsp70. PFA0660w, a type II Hsp40, has been shown to be exported and possibly form a complex with PfHsp70-x in the infected erythrocyte cytosol. However, the chaperone properties of PFA0660w and its interaction with human and parasite Hsp70s are yet to be investigated. Recombinant PFA0660w was found to exist as a monomer in solution, and was able to significantly stimulate the ATPase activity of PfHsp70-x but not that of a second plasmodial Hsp70 (PfHsp70-1) or a human Hsp70 (HSPA1A), indicating a potential specific functional partnership with PfHsp70-x. Protein binding studies in the presence and absence of ATP suggested that the interaction of PFA0660w with PfHsp70-x most likely represented a co-chaperone/chaperone interaction. Also, PFA0660w alone produced a concentration-dependent suppression of rhodanese aggregation, demonstrating its chaperone properties. Overall, we have provided the first biochemical evidence for the possible role of PFA0660w as a chaperone and as co-chaperone of PfHsp70-x. We propose that these chaperones boost the chaperone power of the infected erythrocyte, enabling successful protein trafficking and folding, and thereby making a fundamental contribution to the pathology of malaria. , This work was supported by grants from the National Research Foundation (NRF) and Medical Research Council (MRC) of South Africa. The ProteOn XPR36 IAS was purchased from a National Nanotechnology Equipment Programme grant from the Department of Science and Technology and the NRF of South Africa. Michael O. Daniyan was a recipient of the Education Trust Fund (ETF) Academic Staff Training and Development (AST and D) scholarship of Obafemi Awolowo University, Ile-Ife, Nigeria and a Rhodes University Council research bursary
- Full Text:
- Date Issued: 2016
- Authors: Daniyan, Michael O , Boshoff, Aileen , Prinsloo, Earl , Pesce, Eva-Rachele , Blatch, Gregory L
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66098 , vital:28901 , https://doi.org/10.1371/journal.pone.0148517
- Description: publisher version , Plasmodium falciparum, the human pathogen responsible for the most dangerous malaria infection, survives and develops in mature erythrocytes through the export of proteins needed for remodelling of the host cell. Molecular chaperones of the heat shock protein (Hsp) family are prominent members of the exportome, including a number of Hsp40s and a Hsp70. PFA0660w, a type II Hsp40, has been shown to be exported and possibly form a complex with PfHsp70-x in the infected erythrocyte cytosol. However, the chaperone properties of PFA0660w and its interaction with human and parasite Hsp70s are yet to be investigated. Recombinant PFA0660w was found to exist as a monomer in solution, and was able to significantly stimulate the ATPase activity of PfHsp70-x but not that of a second plasmodial Hsp70 (PfHsp70-1) or a human Hsp70 (HSPA1A), indicating a potential specific functional partnership with PfHsp70-x. Protein binding studies in the presence and absence of ATP suggested that the interaction of PFA0660w with PfHsp70-x most likely represented a co-chaperone/chaperone interaction. Also, PFA0660w alone produced a concentration-dependent suppression of rhodanese aggregation, demonstrating its chaperone properties. Overall, we have provided the first biochemical evidence for the possible role of PFA0660w as a chaperone and as co-chaperone of PfHsp70-x. We propose that these chaperones boost the chaperone power of the infected erythrocyte, enabling successful protein trafficking and folding, and thereby making a fundamental contribution to the pathology of malaria. , This work was supported by grants from the National Research Foundation (NRF) and Medical Research Council (MRC) of South Africa. The ProteOn XPR36 IAS was purchased from a National Nanotechnology Equipment Programme grant from the Department of Science and Technology and the NRF of South Africa. Michael O. Daniyan was a recipient of the Education Trust Fund (ETF) Academic Staff Training and Development (AST and D) scholarship of Obafemi Awolowo University, Ile-Ife, Nigeria and a Rhodes University Council research bursary
- Full Text:
- Date Issued: 2016
Assessment of potential anti-cancer stem cell activity of marine algal compounds using an in vitro mammosphere assay:
- de la Mare, Jo-Anne, Sterrenberg, Jason N, Sukhthankar, Mugdha G, Chiwakata, Maynard T, Beukes, Denzil R, Blatch, Gregory L, Edkins, Adrienne L
- Authors: de la Mare, Jo-Anne , Sterrenberg, Jason N , Sukhthankar, Mugdha G , Chiwakata, Maynard T , Beukes, Denzil R , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165184 , vital:41216 , DOI: 10.1186/1475-2867-13-39
- Description: The cancer stem cell (CSC) theory proposes that tumours arise from and are sustained by a subpopulation of cells with both cancer and stem cell properties. One of the key hallmarks of CSCs is the ability to grow anchorage-independently under serum-free culture conditions resulting in the formation of tumourspheres. It has further been reported that these cells are resistant to traditional chemotherapeutic agents.
- Full Text:
- Date Issued: 2013
- Authors: de la Mare, Jo-Anne , Sterrenberg, Jason N , Sukhthankar, Mugdha G , Chiwakata, Maynard T , Beukes, Denzil R , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165184 , vital:41216 , DOI: 10.1186/1475-2867-13-39
- Description: The cancer stem cell (CSC) theory proposes that tumours arise from and are sustained by a subpopulation of cells with both cancer and stem cell properties. One of the key hallmarks of CSCs is the ability to grow anchorage-independently under serum-free culture conditions resulting in the formation of tumourspheres. It has further been reported that these cells are resistant to traditional chemotherapeutic agents.
- Full Text:
- Date Issued: 2013
Quinones and halogenated monoterpenes of algal origin show anti-proliferative effects against breast cancer cells in vitro:
- de la Mare, Jo-Anne, Lawson, Jessica C, Chiwakata, Maynard T, Beukes, Denzil R, Blatch, Gregory L, Edkins, Adrienne L
- Authors: de la Mare, Jo-Anne , Lawson, Jessica C , Chiwakata, Maynard T , Beukes, Denzil R , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165165 , vital:41214 , DOI: 10.1007/s10637-011-9788-0
- Description: Red and brown algae have been shown to produce a variety of compounds with chemotherapeutic potential. A recent report described the isolation of a range of novel polyhalogenated monoterpene compounds from the red algae Plocamium corallorhiza and Plocamium cornutum collected off the coast of South Africa, together with the previously described tetraprenylquinone, sargaquinoic acid (SQA), from the brown algae Sargassum heterophyllum. In our study, the algal compounds were screened for anti-proliferative activity against metastatic MDA-MB-231 breast cancer cells revealing that a number of compounds displayed anti-cancer activity with IC50 values in the micromolar range. A subset of the compounds was tested for differential toxicity in the MCF-7/MCF12A system and five of these, including sargaquinoic acid, were found to be at least three times more toxic to the breast cancer than the non-malignant cell line.
- Full Text:
- Date Issued: 2012
- Authors: de la Mare, Jo-Anne , Lawson, Jessica C , Chiwakata, Maynard T , Beukes, Denzil R , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165165 , vital:41214 , DOI: 10.1007/s10637-011-9788-0
- Description: Red and brown algae have been shown to produce a variety of compounds with chemotherapeutic potential. A recent report described the isolation of a range of novel polyhalogenated monoterpene compounds from the red algae Plocamium corallorhiza and Plocamium cornutum collected off the coast of South Africa, together with the previously described tetraprenylquinone, sargaquinoic acid (SQA), from the brown algae Sargassum heterophyllum. In our study, the algal compounds were screened for anti-proliferative activity against metastatic MDA-MB-231 breast cancer cells revealing that a number of compounds displayed anti-cancer activity with IC50 values in the micromolar range. A subset of the compounds was tested for differential toxicity in the MCF-7/MCF12A system and five of these, including sargaquinoic acid, were found to be at least three times more toxic to the breast cancer than the non-malignant cell line.
- Full Text:
- Date Issued: 2012
Targeting conserved pathways as a strategy for novel drug development: disabling the cellular stress response:
- Edkins, Adrienne L, Blatch, Gregory L
- Authors: Edkins, Adrienne L , Blatch, Gregory L
- Date: 2012
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/165129 , vital:41211 , ISBN 978-3-642-28174-7 , DOI: 10.1007/978-3-642-28175-4_4
- Description: The ability to respond to and cope with stress at a molecular level is essential for cell survival. The stress response is conserved across organisms by the expression of a group of molecular chaperones known as heat shock proteins (HSP). HSP are ubiquitous and highly conserved proteins that regulate cellular protein homeostasis and trafficking under physiological and stressful conditions, including diseases such as cancer and malaria. HSP are good drug targets for the treatment of human diseases, as the significant functional and structural data available suggest that they are essential for cell survival and that, despite conservation across species, there are biophysical and biochemical differences between HSP in normal and disease states that allow HSP to be selectively targeted. In this chapter, we review the international status of this area of research and highlight progress by us and other African researchers towards the characterisation and targeting of HSP from humans and parasites from Plasmodium and Trypanosoma as drug targets.
- Full Text:
- Date Issued: 2012
- Authors: Edkins, Adrienne L , Blatch, Gregory L
- Date: 2012
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/165129 , vital:41211 , ISBN 978-3-642-28174-7 , DOI: 10.1007/978-3-642-28175-4_4
- Description: The ability to respond to and cope with stress at a molecular level is essential for cell survival. The stress response is conserved across organisms by the expression of a group of molecular chaperones known as heat shock proteins (HSP). HSP are ubiquitous and highly conserved proteins that regulate cellular protein homeostasis and trafficking under physiological and stressful conditions, including diseases such as cancer and malaria. HSP are good drug targets for the treatment of human diseases, as the significant functional and structural data available suggest that they are essential for cell survival and that, despite conservation across species, there are biophysical and biochemical differences between HSP in normal and disease states that allow HSP to be selectively targeted. In this chapter, we review the international status of this area of research and highlight progress by us and other African researchers towards the characterisation and targeting of HSP from humans and parasites from Plasmodium and Trypanosoma as drug targets.
- Full Text:
- Date Issued: 2012
Heat shock proteins as modulators and therapeutic targets of chronic disease: an integrated perspective
- Edkins, Adrienne L, Price, John T, Pockley, A Graham, Blatch, Gregory L
- Authors: Edkins, Adrienne L , Price, John T , Pockley, A Graham , Blatch, Gregory L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164332 , vital:41109 , DOI: 10.1098/rstb.2016.0521
- Description: Many heat shock proteins (HSPs) are essential to survival as a consequence of their role as molecular chaperones, and play a critical role in maintaining cellular proteostasis by integrating the fundamental processes of protein folding and degradation. HSPs are arguably among the most prominent classes of proteins that have been broadly linked to many human disorders, with changes in their expression profile and/or intracellular/extracellular location now being described as contributing to the pathogenesis of a number of different diseases. Although the concept was initially controversial, it is now widely accepted that HSPs have additional biological functions over and above their role in proteostasis (so-called ‘protein moonlighting’).
- Full Text:
- Date Issued: 2017
- Authors: Edkins, Adrienne L , Price, John T , Pockley, A Graham , Blatch, Gregory L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164332 , vital:41109 , DOI: 10.1098/rstb.2016.0521
- Description: Many heat shock proteins (HSPs) are essential to survival as a consequence of their role as molecular chaperones, and play a critical role in maintaining cellular proteostasis by integrating the fundamental processes of protein folding and degradation. HSPs are arguably among the most prominent classes of proteins that have been broadly linked to many human disorders, with changes in their expression profile and/or intracellular/extracellular location now being described as contributing to the pathogenesis of a number of different diseases. Although the concept was initially controversial, it is now widely accepted that HSPs have additional biological functions over and above their role in proteostasis (so-called ‘protein moonlighting’).
- Full Text:
- Date Issued: 2017
The networking of chaperones by co-chaperones: control of cellular protein homeostasis
- Edkins, Adrienne L, Blatch, Gregory L
- Authors: Edkins, Adrienne L , Blatch, Gregory L
- Date: 2014
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/165107 , vital:41209 , ISBN 978-3-319-11731-7
- Description: Co-chaperones are important mediators of the outcome of chaperone assisted protein homeostasis, which is a dynamic balance between the integrated processes of protein folding, degradation and translocation. The Networking of Chaperones by Co-chaperones describes how the function of the major molecular chaperones is regulated by a cohort of diverse non-client proteins, known as co-chaperones. The second edition includes the current status of the field and descriptions of a number of novel co-chaperones that have been recently identified. This new edition has a strong focus on the role of co-chaperones in human disease and as putative drug targets. The book will be a resource for both newcomers and established researchers in the field of cell stress and chaperones, as well as those interested in cross-cutting disciplines such as cellular networks and systems biology.
- Full Text:
- Date Issued: 2014
- Authors: Edkins, Adrienne L , Blatch, Gregory L
- Date: 2014
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/165107 , vital:41209 , ISBN 978-3-319-11731-7
- Description: Co-chaperones are important mediators of the outcome of chaperone assisted protein homeostasis, which is a dynamic balance between the integrated processes of protein folding, degradation and translocation. The Networking of Chaperones by Co-chaperones describes how the function of the major molecular chaperones is regulated by a cohort of diverse non-client proteins, known as co-chaperones. The second edition includes the current status of the field and descriptions of a number of novel co-chaperones that have been recently identified. This new edition has a strong focus on the role of co-chaperones in human disease and as putative drug targets. The book will be a resource for both newcomers and established researchers in the field of cell stress and chaperones, as well as those interested in cross-cutting disciplines such as cellular networks and systems biology.
- Full Text:
- Date Issued: 2014
A Trypanosoma cruzi heat shock protein 40 is able to stimulate the adenosine triphosphate hydrolysis activity of heat shock protein 70 and can substitute for a yeast heat shock protein 40
- Edkins, Adrienne L, Ludewig, M H, Blatch, Gregory L
- Authors: Edkins, Adrienne L , Ludewig, M H , Blatch, Gregory L
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6465 , http://hdl.handle.net/10962/d1005794 , http://dx.doi.org/10.1016/j.biocel.2004.01.016
- Description: The process of assisted protein folding, characteristic of members of the heat shock protein 70 (Hsp70) and heat shock protein 40 (Hsp40) molecular chaperone families, is important for maintaining the structural integrity of cellular protein machinery under normal and stressful conditions. Hsp70 and Hsp40 cooperate to bind non-native protein conformations in a process of adenosine triphosphate (ATP)-regulated assisted protein folding. We have analysed the molecular chaperone activity of the cytoplasmic inducible Hsp70 from Trypanosoma cruzi (TcHsp70) and its interactions with its potential partner Hsp40s (T. cruzi DnaJ protein 1 [Tcj1] and T. cruzi DnaJ protein 2 [Tcj2]). Histidine-tagged TcHsp70 (His-TcHsp70), Tcj1 (Tcj1-His) and Tcj2 (His-Tcj2) were over-produced in Escherichia coli and purified by nickel affinity chromatography. The in vitro basal specific ATP hydrolysis activity (ATPase activity) of His-TcHsp70 was determined as 40 nmol phosphate/min/mg protein, significantly higher than that reported for other Hsp70s. The basal specific ATPase activity was stimulated to a maximal level of 60 nmol phosphate/min/mg protein in the presence of His-Tcj2 and a model substrate, reduced carboxymethylated α-lactalbumin. In vivo complementation assays showed that Tcj2 was able to overcome the temperature sensitivity of the ydj1 mutant Saccharomyces cerevisiae strain JJ160, suggesting that Tcj2 may be functionally equivalent to the yeast Hsp40 homologue (yeast DnaJ protein 1, Ydj1). These data suggest that Tcj2 is involved in cytoprotection in a similar fashion to Ydj1, and that TcHsp70 and Tcj2 may interact in a nucleotide-regulated process of chaperone-assisted protein folding.
- Full Text:
- Date Issued: 2004
- Authors: Edkins, Adrienne L , Ludewig, M H , Blatch, Gregory L
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6465 , http://hdl.handle.net/10962/d1005794 , http://dx.doi.org/10.1016/j.biocel.2004.01.016
- Description: The process of assisted protein folding, characteristic of members of the heat shock protein 70 (Hsp70) and heat shock protein 40 (Hsp40) molecular chaperone families, is important for maintaining the structural integrity of cellular protein machinery under normal and stressful conditions. Hsp70 and Hsp40 cooperate to bind non-native protein conformations in a process of adenosine triphosphate (ATP)-regulated assisted protein folding. We have analysed the molecular chaperone activity of the cytoplasmic inducible Hsp70 from Trypanosoma cruzi (TcHsp70) and its interactions with its potential partner Hsp40s (T. cruzi DnaJ protein 1 [Tcj1] and T. cruzi DnaJ protein 2 [Tcj2]). Histidine-tagged TcHsp70 (His-TcHsp70), Tcj1 (Tcj1-His) and Tcj2 (His-Tcj2) were over-produced in Escherichia coli and purified by nickel affinity chromatography. The in vitro basal specific ATP hydrolysis activity (ATPase activity) of His-TcHsp70 was determined as 40 nmol phosphate/min/mg protein, significantly higher than that reported for other Hsp70s. The basal specific ATPase activity was stimulated to a maximal level of 60 nmol phosphate/min/mg protein in the presence of His-Tcj2 and a model substrate, reduced carboxymethylated α-lactalbumin. In vivo complementation assays showed that Tcj2 was able to overcome the temperature sensitivity of the ydj1 mutant Saccharomyces cerevisiae strain JJ160, suggesting that Tcj2 may be functionally equivalent to the yeast Hsp40 homologue (yeast DnaJ protein 1, Ydj1). These data suggest that Tcj2 is involved in cytoprotection in a similar fashion to Ydj1, and that TcHsp70 and Tcj2 may interact in a nucleotide-regulated process of chaperone-assisted protein folding.
- Full Text:
- Date Issued: 2004
Plasmodium falciparum Hsp70-x : a heat shock protein at the host-parasite interface
- Hatherley, R, Blatch, Gregory L, Tastan Bishop, Özlem
- Authors: Hatherley, R , Blatch, Gregory L , Tastan Bishop, Özlem
- Date: 2013
- Language: English
- Type: Article
- Identifier: vital:6489 , http://hdl.handle.net/10962/d1007081 , https://dx.doi.org/10.1080/07391102.2013.834849
- Description: Plasmodium falciparum 70 kDa heat shock proteins (PfHsp70s) are expressed at all stages of the pathogenic erythrocytic phase of the malaria parasite lifecycle. There are six PfHsp70s,all of which have orthologues in other plasmodial species, except for PfHsp70-x which is unique to P. falciparum. This paper highlights a number of original results obtained by a detailed bioinformatics analysis of the protein. Large scale sequence analysis indicated the presence of an extended transit peptide sequence of PfHsp70-x which potentially directs it to the endoplasmic reticulum (ER). Further analysis showed that PfHsp70-x does not have an ER-retention sequence, suggesting that the protein transits through the ER and is secreted into the parasitophorous vacuole (PV) or beyond into the erythrocyte cytosol. These results are consistent with experimental findings. Next, possible interactions between PfHsp70-x and exported P. falciparum Hsp40s or host erythrocyte DnaJs were interrogated by modeling and docking. Docking results indicated that interaction between PfHsp70-x and each of the Hsp40s, regardless of biological feasibility, seems equally likely. This suggests that J domain might not provide the specificity in the formation of unique Hsp70-Hsp40 complexes, but that the specificity might be provided by other domains of Hsp40s. By studying different structural conformations of PfHsp70-x, it was shown that Hsp40s can only bind when PfHsp70-x is in a certain conformation. Additionally, this work highlighted the possible dependence of the substrate binding domain residues on the orientation of the α-helical lid for formation of the substrate binding pocket.
- Full Text:
- Date Issued: 2013
- Authors: Hatherley, R , Blatch, Gregory L , Tastan Bishop, Özlem
- Date: 2013
- Language: English
- Type: Article
- Identifier: vital:6489 , http://hdl.handle.net/10962/d1007081 , https://dx.doi.org/10.1080/07391102.2013.834849
- Description: Plasmodium falciparum 70 kDa heat shock proteins (PfHsp70s) are expressed at all stages of the pathogenic erythrocytic phase of the malaria parasite lifecycle. There are six PfHsp70s,all of which have orthologues in other plasmodial species, except for PfHsp70-x which is unique to P. falciparum. This paper highlights a number of original results obtained by a detailed bioinformatics analysis of the protein. Large scale sequence analysis indicated the presence of an extended transit peptide sequence of PfHsp70-x which potentially directs it to the endoplasmic reticulum (ER). Further analysis showed that PfHsp70-x does not have an ER-retention sequence, suggesting that the protein transits through the ER and is secreted into the parasitophorous vacuole (PV) or beyond into the erythrocyte cytosol. These results are consistent with experimental findings. Next, possible interactions between PfHsp70-x and exported P. falciparum Hsp40s or host erythrocyte DnaJs were interrogated by modeling and docking. Docking results indicated that interaction between PfHsp70-x and each of the Hsp40s, regardless of biological feasibility, seems equally likely. This suggests that J domain might not provide the specificity in the formation of unique Hsp70-Hsp40 complexes, but that the specificity might be provided by other domains of Hsp40s. By studying different structural conformations of PfHsp70-x, it was shown that Hsp40s can only bind when PfHsp70-x is in a certain conformation. Additionally, this work highlighted the possible dependence of the substrate binding domain residues on the orientation of the α-helical lid for formation of the substrate binding pocket.
- Full Text:
- Date Issued: 2013
Not all J domains are created equal: implications for the specificity of Hsp40-Hsp70 interactions
- Hennessy, Fritha, Nicoll, Willam S, Zimmerman, Richard, Cheetham, Michael E, Blatch, Gregory L
- Authors: Hennessy, Fritha , Nicoll, Willam S , Zimmerman, Richard , Cheetham, Michael E , Blatch, Gregory L
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6487 , http://hdl.handle.net/10962/d1006270 , http://dx.doi.org/10.1110/ps.051406805
- Description: Heat shock protein 40s (Hsp40s) and heat shock protein 70s (Hsp70s) form chaperone partnerships that are key components of cellular chaperone networks involved in facilitating the correct folding of a broad range of client proteins. While the Hsp40 family of proteins is highly diverse with multiple forms occurring in any particular cell or compartment, all its members are characterized by a J domain that directs their interaction with a partner Hsp70. Specific Hsp40-Hsp70 chaperone partnerships have been identified that are dedicated to the correct folding of distinct subsets of client proteins. The elucidation of the mechanism by which these specific Hsp40-Hsp70 partnerships are formed will greatly enhance our understanding of the way in which chaperone pathways are integrated into finely regulated protein folding networks. From in silico analyses, domain swapping and rational protein engineering experiments, evidence has accumulated that indicates that J domains contain key specificity determinants. This review will critically discuss the current understanding of the structural features of J domains that determine the specificity of interaction between Hsp40 proteins and their partner Hsp70s. We also propose a model in which the J domain is able to integrate specificity and chaperone activity.
- Full Text:
- Date Issued: 2005
- Authors: Hennessy, Fritha , Nicoll, Willam S , Zimmerman, Richard , Cheetham, Michael E , Blatch, Gregory L
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6487 , http://hdl.handle.net/10962/d1006270 , http://dx.doi.org/10.1110/ps.051406805
- Description: Heat shock protein 40s (Hsp40s) and heat shock protein 70s (Hsp70s) form chaperone partnerships that are key components of cellular chaperone networks involved in facilitating the correct folding of a broad range of client proteins. While the Hsp40 family of proteins is highly diverse with multiple forms occurring in any particular cell or compartment, all its members are characterized by a J domain that directs their interaction with a partner Hsp70. Specific Hsp40-Hsp70 chaperone partnerships have been identified that are dedicated to the correct folding of distinct subsets of client proteins. The elucidation of the mechanism by which these specific Hsp40-Hsp70 partnerships are formed will greatly enhance our understanding of the way in which chaperone pathways are integrated into finely regulated protein folding networks. From in silico analyses, domain swapping and rational protein engineering experiments, evidence has accumulated that indicates that J domains contain key specificity determinants. This review will critically discuss the current understanding of the structural features of J domains that determine the specificity of interaction between Hsp40 proteins and their partner Hsp70s. We also propose a model in which the J domain is able to integrate specificity and chaperone activity.
- Full Text:
- Date Issued: 2005
Cancer stem cells in breast cancer and metastasis:
- Lawson, Jessica C, Blatch, Gregory L, Edkins, Adrienne L
- Authors: Lawson, Jessica C , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165057 , vital:41205 , DOI: 10.1007/s10549-009-0524-9
- Description: The cancer stem cell theory poses that cancers develop from a subset of malignant cells that possess stem cell characteristics and has been proposed to account for the development of a variety of malignancies, including breast cancer. These cancer stem cells (CSC) possess characteristics of both stem cells and cancer cells, in that they have the properties of self-renewal, asymmetric cell division, resistance to apoptosis, independent growth, tumourigenicity and metastatic potential. A CSC origin for breast cancer can neatly explain both the heterogeneity of breast cancers and the relapse of the tumours after treatment. However, many reports on CSC in the breast are contradictory. There is variation with respect to how breast cancer stem cells should be identified, their characteristics and a possible lack of correlation between clinical outcome and breast cancer stem cell status of a tumour. These combined factors have made breast cancer stem cells a highly contentious issue. In this review, we highlight the progress in the analysis of cancer stem cells, with an emphasis on breast cancer.
- Full Text:
- Date Issued: 2009
- Authors: Lawson, Jessica C , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165057 , vital:41205 , DOI: 10.1007/s10549-009-0524-9
- Description: The cancer stem cell theory poses that cancers develop from a subset of malignant cells that possess stem cell characteristics and has been proposed to account for the development of a variety of malignancies, including breast cancer. These cancer stem cells (CSC) possess characteristics of both stem cells and cancer cells, in that they have the properties of self-renewal, asymmetric cell division, resistance to apoptosis, independent growth, tumourigenicity and metastatic potential. A CSC origin for breast cancer can neatly explain both the heterogeneity of breast cancers and the relapse of the tumours after treatment. However, many reports on CSC in the breast are contradictory. There is variation with respect to how breast cancer stem cells should be identified, their characteristics and a possible lack of correlation between clinical outcome and breast cancer stem cell status of a tumour. These combined factors have made breast cancer stem cells a highly contentious issue. In this review, we highlight the progress in the analysis of cancer stem cells, with an emphasis on breast cancer.
- Full Text:
- Date Issued: 2009
Nuclear translocation of the Hsp70/Hsp90 organizing protein mSTI1 is regulated by cell cycle kinases
- Longshaw, Victoria M, Chapple, J Paul, Cheetham, Michael E, Blatch, Gregory L
- Authors: Longshaw, Victoria M , Chapple, J Paul , Cheetham, Michael E , Blatch, Gregory L
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6488 , http://hdl.handle.net/10962/d1006271 , https://dx.doi.org/10.1242/jcs.00905
- Description: The co-chaperone murine stress-inducible protein 1 (mSTI1), an Hsp70/Hsp90 organizing protein (Hop) homologue, mediates the assembly of the Hsp70/Hsp90 chaperone heterocomplex. The mSTI1 protein can be phosphorylated in vitro by cell cycle kinases proximal to a putative nuclear localization signal (NLS), which substantiated a predicted casein kinase II (CKII)-cdc2 kinase-NLS (CcN) motif at position 180-239 and suggested that mSTI1 might move between the cytoplasm and the nucleus under certain cell cycle conditions. The mechanism responsible for the cellular localization of mSTI1 was probed using NIH3T3 fibroblasts to investigate the localization of endogenous mSTI1 and enhanced green fluorescent protein (EGFP)-tagged mSTI1 mutants. Localization studies on cell lines stably expressing NLS(mSTI1)-EGFP and EGFP demonstrated that the NLS(mSTI1) was able to promote a nuclear localization of EGFP. The mSTI1 protein was exclusively cytoplasmic in most cells under normal conditions but was present in the nucleus of a subpopulation of cells and accumulated in the nucleus following inhibition of nuclear export (leptomycin B treatment). G1/S-phase arrest (using hydroxyurea) and inhibition of cdc2 kinase (using olomoucine) but not inhibition of casein kinase II (using 5,6-dichlorobenzimidazole riboside), increased the proportion of cells with endogenous mSTI1 nuclear staining. mSTI1-EGFP behaved identically to endogenous mSTI1. The functional importance of key residues was tested using modified mSTI1-EGFP proteins. Inactivation and phosphorylation mimicking of potential phosphorylation sites in mSTI1 altered the nuclear translocation. Mimicking of phosphorylation at the mSTI1 CKII phosphorylation site (S189E) promoted nuclear localization of mSTI1-EGFP. Mimicking phosphorylation at the cdc2 kinase phosphorylation site (T198E) promoted cytoplasmic localization of mSTI1-EGFP at the G1/S-phase transition,whereas removal of this site (T198A) promoted the nuclear localization of mSTI1-EGFP under the same conditions. These data provide the first evidence of nuclear import and export of a major Hsp70/Hsp90 co-chaperone and the regulation of this nuclear-cytoplasmic shuttling by cell cycle status and cell cycle kinases.
- Full Text:
- Date Issued: 2004
Nuclear translocation of the Hsp70/Hsp90 organizing protein mSTI1 is regulated by cell cycle kinases
- Authors: Longshaw, Victoria M , Chapple, J Paul , Cheetham, Michael E , Blatch, Gregory L
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6488 , http://hdl.handle.net/10962/d1006271 , https://dx.doi.org/10.1242/jcs.00905
- Description: The co-chaperone murine stress-inducible protein 1 (mSTI1), an Hsp70/Hsp90 organizing protein (Hop) homologue, mediates the assembly of the Hsp70/Hsp90 chaperone heterocomplex. The mSTI1 protein can be phosphorylated in vitro by cell cycle kinases proximal to a putative nuclear localization signal (NLS), which substantiated a predicted casein kinase II (CKII)-cdc2 kinase-NLS (CcN) motif at position 180-239 and suggested that mSTI1 might move between the cytoplasm and the nucleus under certain cell cycle conditions. The mechanism responsible for the cellular localization of mSTI1 was probed using NIH3T3 fibroblasts to investigate the localization of endogenous mSTI1 and enhanced green fluorescent protein (EGFP)-tagged mSTI1 mutants. Localization studies on cell lines stably expressing NLS(mSTI1)-EGFP and EGFP demonstrated that the NLS(mSTI1) was able to promote a nuclear localization of EGFP. The mSTI1 protein was exclusively cytoplasmic in most cells under normal conditions but was present in the nucleus of a subpopulation of cells and accumulated in the nucleus following inhibition of nuclear export (leptomycin B treatment). G1/S-phase arrest (using hydroxyurea) and inhibition of cdc2 kinase (using olomoucine) but not inhibition of casein kinase II (using 5,6-dichlorobenzimidazole riboside), increased the proportion of cells with endogenous mSTI1 nuclear staining. mSTI1-EGFP behaved identically to endogenous mSTI1. The functional importance of key residues was tested using modified mSTI1-EGFP proteins. Inactivation and phosphorylation mimicking of potential phosphorylation sites in mSTI1 altered the nuclear translocation. Mimicking of phosphorylation at the mSTI1 CKII phosphorylation site (S189E) promoted nuclear localization of mSTI1-EGFP. Mimicking phosphorylation at the cdc2 kinase phosphorylation site (T198E) promoted cytoplasmic localization of mSTI1-EGFP at the G1/S-phase transition,whereas removal of this site (T198A) promoted the nuclear localization of mSTI1-EGFP under the same conditions. These data provide the first evidence of nuclear import and export of a major Hsp70/Hsp90 co-chaperone and the regulation of this nuclear-cytoplasmic shuttling by cell cycle status and cell cycle kinases.
- Full Text:
- Date Issued: 2004
The TPR2B domain of the Hsp70/Hsp90 organizing protein (Hop) may contribute towards its dimerization
- Longshaw, Victoria M, Stephens, Linda L, Daniel, Sheril, Blatch, Gregory L
- Authors: Longshaw, Victoria M , Stephens, Linda L , Daniel, Sheril , Blatch, Gregory L
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6481 , http://hdl.handle.net/10962/d1006253 , http://dx.doi.org/10.2174/092986609787848162
- Description: The role of the TPR2B domain of Hop is as yet unknown. We have shown here by site directed mutagenesis and size exclusion chromatography for the first time that the TPR1 and TPR2B domains of Hop independently dimerized, and that the dimerization of TPR2B was not dependent on its predicted two-carboxylate clamp residues. Furthermore, our data indicated that the dimerization of Hop and its domains was not disrupted in the presence of Hsp70 and Hsp90 peptides.
- Full Text:
- Date Issued: 2009
The TPR2B domain of the Hsp70/Hsp90 organizing protein (Hop) may contribute towards its dimerization
- Authors: Longshaw, Victoria M , Stephens, Linda L , Daniel, Sheril , Blatch, Gregory L
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6481 , http://hdl.handle.net/10962/d1006253 , http://dx.doi.org/10.2174/092986609787848162
- Description: The role of the TPR2B domain of Hop is as yet unknown. We have shown here by site directed mutagenesis and size exclusion chromatography for the first time that the TPR1 and TPR2B domains of Hop independently dimerized, and that the dimerization of TPR2B was not dependent on its predicted two-carboxylate clamp residues. Furthermore, our data indicated that the dimerization of Hop and its domains was not disrupted in the presence of Hsp70 and Hsp90 peptides.
- Full Text:
- Date Issued: 2009
HOP expression is regulated by p53 and RAS and characteristic of a cancer gene signature
- Mattison, Stacey A, Blatch, Gregory L, Edkins, Adrienne L
- Authors: Mattison, Stacey A , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66278 , vital:28928 , https://doi.org/10.1007/s12192-016-0755-8
- Description: publisher version , The Hsp70/Hsp90 organising protein (HOP) is a co-chaperone essential for client protein transfer from Hsp70 to Hsp90 within the Hsp90 chaperone machine. Although HOP is upregulated in various cancers, there is limited information from in vitro studies on how HOP expression is regulated in cancer. The main objective of this study was to identify the HOP promoter and investigate its activity in cancerous cells. Bioinformatic analysis of the -2500 to +16 bp region of the HOP gene identified a large CpG island and a range of putative cis-elements. Many of the cis-elements were potentially bound by transcription factors which are activated by oncogenic pathways. Luciferase reporter assays demonstrated that the upstream region of the HOP gene contains an active promoter in vitro. Truncation of this region suggested that the core HOP promoter region was -855 to +16 bp. HOP promoter activity was highest in Hs578T, HEK293T and SV40- transformed MEF1 cell lines which expressed mutant or inactive p53. In a mutant p53 background, expression of wild-type p53 led to a reduction in promoter activity, while inhibition of wild-type p53 in HeLa cells increased HOP promoter activity. Additionally, in Hs578T and HEK293T cell lines containing inactive p53, expression of HRAS increased HOP promoter activity. However, HRAS activation of the HOP promoter was inhibited by p53 overexpression. These findings suggest for the first time that HOP expression in cancer may be regulated by both RAS activation and p53 inhibition. Taken together, these data suggest that HOP may be part of the cancer gene signature induced by a combination of mutant p53 and mutated RAS that is associated with cellular transformation.
- Full Text: false
- Date Issued: 2018
- Authors: Mattison, Stacey A , Blatch, Gregory L , Edkins, Adrienne L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66278 , vital:28928 , https://doi.org/10.1007/s12192-016-0755-8
- Description: publisher version , The Hsp70/Hsp90 organising protein (HOP) is a co-chaperone essential for client protein transfer from Hsp70 to Hsp90 within the Hsp90 chaperone machine. Although HOP is upregulated in various cancers, there is limited information from in vitro studies on how HOP expression is regulated in cancer. The main objective of this study was to identify the HOP promoter and investigate its activity in cancerous cells. Bioinformatic analysis of the -2500 to +16 bp region of the HOP gene identified a large CpG island and a range of putative cis-elements. Many of the cis-elements were potentially bound by transcription factors which are activated by oncogenic pathways. Luciferase reporter assays demonstrated that the upstream region of the HOP gene contains an active promoter in vitro. Truncation of this region suggested that the core HOP promoter region was -855 to +16 bp. HOP promoter activity was highest in Hs578T, HEK293T and SV40- transformed MEF1 cell lines which expressed mutant or inactive p53. In a mutant p53 background, expression of wild-type p53 led to a reduction in promoter activity, while inhibition of wild-type p53 in HeLa cells increased HOP promoter activity. Additionally, in Hs578T and HEK293T cell lines containing inactive p53, expression of HRAS increased HOP promoter activity. However, HRAS activation of the HOP promoter was inhibited by p53 overexpression. These findings suggest for the first time that HOP expression in cancer may be regulated by both RAS activation and p53 inhibition. Taken together, these data suggest that HOP may be part of the cancer gene signature induced by a combination of mutant p53 and mutated RAS that is associated with cellular transformation.
- Full Text: false
- Date Issued: 2018